### Video Transcript

A tutor gives his two students a
quiz. The two stopwatches show the time
taken by Liam and Jacob to solve the quiz. What is the time taken by each of
them, respectively, in seconds? Who finishes the quiz first?

This question describes two
students, Liam and Jacob, who’ve been given a quiz to do by their tutor. It seems like it was a little bit
of a competition because we’re shown two stopwatches which show the time taken by
each of these two students to finish the quiz. The first part of our problem asks
us to find the time that it takes both Liam and Jacob to solve the quiz in
seconds. This word “respectively” here isn’t
as complicated as it looks. It just means in the order that
they’ve been mentioned. So when we work out both times, we
need to say Liam’s time first and then Jacob’s. Now, when both students started the
quiz, the stopwatch would’ve looked a little bit like this.

As soon as the tutor started
timing, the digits to the right of the two dots would’ve slowly increased, one, two,
and so on. These digits show the number of
seconds that have gone by. And we know with stopwatches like
this, the two digits to the left of the two dots show the number of minutes that
have gone by. So we can see straightaway how long
each student took. Liam’s stopwatch shows one minute,
10 seconds. And Jacob’s shows one minute, 25
seconds. But there’s a slight problem here
because we’re told to give the times in seconds. In other words, we’re gonna have to
convert between a time given in minutes and seconds to just seconds.

And to help us, we’re going to have
to remember a fact about minutes and seconds. This bar model shows Liam’s time of
one minute, 10 seconds. Do you remember how many seconds
there are in a minute? One minute is the same as 60
seconds. And 60 seconds plus another 10
seconds equals 70 seconds altogether. And we can use a similar bar model
to help convert Jacob’s time into seconds. He took one minute, 25 seconds,
which is the same as 60 seconds plus 25 seconds, which is 85 seconds in total. And as we’ve said, we need to give
these times in the order that they’re mentioned, so Liam’s time and then
Jacob’s.

In the final part of the problem,
we’re asked, “Who finishes the quiz first?” And because we’ve converted both
times into a number of seconds, we can just compare the numbers. 70 is less than 85. And when we’re talking about time,
the quicker we do something, the less time it takes or the less number of seconds it
takes. Liam’s taken less time, and so he
finishes the quiz first.

This question tested our ability to
read digital stopwatches but also how to convert between a time in minutes and
seconds to a time just in seconds. We knew that there were 60 seconds
in a minute, and this helped us. The time taken by each student to
complete the quiz, in seconds, in the order that they’re mentioned, is 70 seconds
and 85 seconds. And so we know the student who
finishes the quiz first is Liam.